This invention relates to planetary gearing systems and more particularly to structures for attaching rotatable orbiting planet gears to the planet gear carrier of such systems.
Planetary gearing systems are used in a variety of mechanisms in which rotary drive is to be transmitted while realizing a speed reduction or speed increase accompanied by a torque increase or reduction. The drive connections between a motor and a wheel of a vehicle is one example of mechanism in which planetary gearing systems are often used. While planetary gearing systems may take a variety of specific forms, all have in common a planet gear carrier supported for rotation about a primary axis and carrying one or more planet gears which may orbit about the primary axis while also being rotatable about a secondary orbiting axis which is parallel to the primary axis. Depending on the type of planetary gearing system, the planet gears may engage one or both of a sun gear and a ring gear which are both disposed coaxially with respect to the primary axis.
To attach the planet gears to the carrier some form of axle pin is mounted on the carrier and extends through an axial bore of the associated planet gear to journal the planet gear in position. In some cases the axle pins have been rotationally fixed relative to the carrier so that the planet gear turns on the pin while in other cases the axle turns with the planet gear which rotates relative to the carrier. Depending on which type of arrangement is used, the axle pin may be restrained against longitudinal displacement by a friction fit in either the gear or in the carrier except where complex retainer means have been provided.
Planetary gearing systems usually operate within a housing containing lubricant and heretofore it has been the more common practice to assume that adequate lubrication occurs at the planet gear bearing surfaces simply by reason of the fact that the planet gears sweep through the adjacent volume of lubricant during operation.
The above-described prior constructions complicate the process of assembling and disassembling planetary gearing systems and it may be found that there is not in fact adequate lubrication of planet gear bearing surfaces with the result that wear is accelerated and energy is dissipated in the form of undesirable heating of the mechanism.